Process of dyeing anodic oxidized coating of aluminium or its alloys



March 14, 1939. Y. YASOSHIMA PROCESS OF DYEING ANODIC OXTDIZED COATING ALUMINIUM OR ITS ALLOYS Filed June 25, 1957 AW? 0M hum T ,N MW o m 5 m M Cu K m Patented Mar. 14, 1939 UNITED STATES success or rams ANODIO oximzun comma or ALUMINIUM on rrs more Yakichi 'Yasoshima, Mulroyanagiwara-Machi, Asakusa-ku, Tokyo, Japan, assignor to Biken Arumaitokogyo Kabushiki Kaisha, Tokyo,

japan, a corporation of Japan Application June 25, 1937, Serial No. 150,42 2' Claims. (01. 41-29) The present invention relates to a process of dyeing an ano'dic oxidized coating on aluminium or its alloys, which consists in combination of the step of subjecting aluminium or its alloys t the so-called electro-chemical anodic treatment, printing desired figures such as lines, designs, etc., on the surface of the porous oxidized coating formed on the surface of aluminium or its alloys by the above treatment, with a saponifiable 1o fatty varnish preparation having a reservative property, and then dyeing the remaining portion of said coating with dyestuffs, for example, a direct dyestufi, acidic dyestufi, basic dyestuilf or mordant color and the step of filling the pores lb of the said dyed portion with the soap produced by the treatment of the whole with an alkali hydroxide, for instance, caustic potash. solution and the consequent saponification of the remaining attached saponifiable fatty printing varnish preparation with said alkali. Thus, according to the present invention it is possible to dye an anodic oxidized coating of aluminium or its allofys simply and accurately and at the same time impregnate the whole surface with a layer of,

5 soap and thus produce thereon the elegant lustre of a lacquer.

In the accompanying drawing forming part hereof.

Figure l is an ,enlarged fragmentary section of a piece of aluminium or of an aluminium alloy having a porous oxide coating formed on its surface by an electro-chemical anodic treatment.

Figure 2 is a similar view showing the condition when the coating is colored and the pores are filled with a soap according to the invention.

The following is an example of performing this invention:-

This invention employs as a printing preparation a kind of fatty printing varnish prepared by mixing suitably a fatty substance, mainly linseed oil belonging to dry oil, a resinous substance such as China copal and metal soap like lead soap.

The following is an example ofpreparing the [5 fatty printing varnish employed in this invention:

Per cent by weight Linseed 40 50 China copa 20 Metal soap 40 In the drawing, the aluminium'or alloy thereof is indicated at i, while 2 indicates a porous ox- 55 ide coating formed on the surface of the same,

and 3 refers to the pores in said coating. In Figure 2, the soap which fills the pores is indicated at d. V

With the mentioned fatty printing varnish preparation having preservative characteristics 5 thus obtained, desired figures are printed upon the surface of an anodic oxidized coating of aluminium or its alloys, using a rubber plate, lithographic slate, etc., thus depriving that part of the surface of the dyeing power of a dyestufl. 30

Next, after drying it suitably, the remaining portion of said coating is dyed with a desired dyestuff. If on this occasion it is desired to have a deep and durable color, use is especially made of a direct dyestufl. But oppositely if a fresh light in color is preferable, it is advisable to take an acidic dyestufl. Although a basic dyestufl and mordant color are inferior to the above direct dyestuflz and an acidic dyestuif in dyeing power,

they also may be used. As a direct dyestuff, all a kinds of direct dyestuffs, for example, diazophenyl black, diamine black and oxvdiamine violet are employed, while as for an acidic dyestufif all kinds of direct dyestuffs, for instance, acid black, fast green and suiphon orange are avail- 25 able. Then, the whole of said anodic oxidized coating is treated in alkali hydroxide, for example, caustic potash solution-containing hot liquor to dissolve and remove those parts of said saponifiable fatty varnish preparation that have. 30 swollen on the above coating, and the dissolved fatty varnish and alkali hydroxide will form a kind of soap by saponification. In the present invention, by filling the pores of said dyed portion with the soap thus produced and thus impreg- 35 mating the whole surface uniformly with a soap layer, it is possible to produce thereon the elegant lustre of a lacquer.

Incidentally, before use, said fatty printing varnish preparation may have dissolved therein about 10% of a basic pigment which doesnot dye anodic oxidized coatings of aluminium or its alloys, or an oil-soluble basic pigment such as gives a suitable color to said anodic oxidized coating as a guide color for distinguishing the color of the printed figures clearly from that of the oxidized coating.

The dyeing process according to this invention may be, on the other hand, called a process. of producing a fatty anodic oxidized coating upon aluminium or its alloys. its production does not only have the elegant lustre of the lacquer, but also if it is applied to, for instance, the dyeing of 'a sound record, theneedle can run smoothly on the record in the recording of r a sound, thus ing oi aluminium, which consists in subjecting aluminium to an electro-chemical anodic treatment, printing desired figures such as lines, designs, etc. on the porous oxidized coating formed on the surface of said aluminium by the above treatment, with a saponiflable fatty printing varnish preparation having a preservative property and dyeing the remaining portion 01 said coating with a dyestufl', and then filling the pores of such dyed portion with the soap prepared by the treatment or the whole with an alkali hydroxide and 1. Process 0: dyeing an anodic oxidized coat the consequent saponiflcation oi the remaining attached saponifiable iatty printing varnish preparation with said alkali.

2. Process oi dyeing an anodlc oxidized coating or aluminium alloys, which consists in sub- Jecting aluminium alloys to an electro-chemical anodic treatment, printing desired figures such as lines, designs, etc. on the porous oxidized coating formed on the surface or said aluminium alloys by the above treatment, with a saponiflable iatty printing varnish preparation having a preservative property and dyeing the remaining portion of said coating with a dyestufl, and then fllling the pores of such dyed portion with the soap prepared by the treatment or the whole with an alkali hydroxide and the consequent saponiflcation oi the remaining attached saponiflable Iatty printing varnish preparation with said alkali. YAKICHI YASOBHIMA. 

